题目

下列反应的离子方程式正确的是（     ）A．将标准状况下112 mL氯气通入10mL1 mol/L的溴化亚铁溶液中：2Fe2++4Br－+3Cl2==2Fe3++2Br2+6Cl－B．滴有稀硫酸的淀粉碘化钾溶液在空气中变蓝：2I－+O2+4H+=== I2+2H2OC．SO2溶液使酸性KMnO4溶液褪色：5SO2+ 2MnO4－+2H2O === 5SO42－ + 2Mn2++ 4 H+D．向次氯酸钙溶液中通入SO2： Ca2++ 2ClO－+ SO2+H2O === CaSO3↓+2HClO ________the American economy expanded at an annual rate of 2.5 percent in July—September, it faced a long road to recovery.A．Since　B．IfC．While　D．When